Centrifugal separator



Patented F el). 16, 1925.

PATENT' OFFICE.`

JOHN IVI.' NICOL, OF MILL VALLEY, CALIFORNIA.

CENTRIFUGAL SEPARATOR.

Application filed August 28, 1923. Serial No. 659,727.

To aZZ whom t may concern.'

Be it known that I, JOHN MALCOLM Nicci., a subject of the King of GreatBritain, a resident of Mill Valley, in the county of Marin and State ofCalifornia, have invented a certain new and useful CentrifugalSeparator, of which the following is a specification. i

rllhis invention relates to a centrifugal machine, and more particularlyto a centrifugal machine for use in metallurgical operations for theseparation of fine gold and platinum and other heavy minerals fromassociated fine sands, and for like purposes.

This invention has as an object a centrifugal apparatus designed toseparate two or more minerals or other-materials from each v other toprovide separate products. Another A CFI object of the invention is toprovide a form of apparatus that will be capable of concentrating outvaluable metals such as gold and platinum from worthless associatedsands or other metalliferous materials. A further object is to providean apparatus for the treatf ment of sulphide minerals and the clean-upof dredging operations. Still another object 0f the invention is toprovide an apparatus which will separate and concentrate niaterials bycentrifugal action in such a manner that each particle is given adiiferential rotation during the course of the treatment so thata cleanseparation will be obtained. A still further object is to provide suchan apparatus that will have means for regulating the amount ofdischarged concentrate while the machine is ruiming, so that the hnestadjustments may be made, and also to provide means for separating two ormore concentrates, Further objects of the invention will appear as thefollowing description proceeds.

Vilhile the apparatus described is intended for use in connection withmetallurgical operations, it is to be understood that its structure isnotl peculiarly limited thereto, but may be used for centrifugaloperations in the chemical industryT and elsewhere where a Vmachine ofits structure is of value. Thilo the invention may be represented invarious embodiments, it is desired in the following preferred embodimentto describe a particu.

lar form of appa 'atus that is peculiarly adapted to certainmetallurgical operations.

Accordingly the invention in its preferred embodiment is illustrated onthe accompanying` sheet of drawings, in which,-

Fig. l represents a vertical central section of the centrifugalseparator, and

Fig. 2 represents a modification of a part of the structure comprisingthe inner bowl.

In the aforesaid preferred embodiment, there is shown a main supportingframe l that carries an upper cross member 2 and a lower cross member 3.The upper cross member carries a removable angle bracket l serving asthe supporting means for an upper bearing, and the lower cross membercarries another removable angle bucket 5 serving to support a lowerbearing, these bearings serving to support the revolving parts to bedescribed later. 'lhere is also provided'a footstep block 6 having anoil well 7 and an adjustable center pivot 8, and a preferably brassbushed central vertical bearing 9.

The main revolving member in which the centrifugal effect is producedconsists of a bowl l0 into the bottom of which is screwed a footstepshaft l1 held by a set screw The shaft ll revolves freely in the bearing9 and rests on the pivot of the screw S, this mechanism being finelybalanced so that the bowl will not revolve irregularly during operation.rl`he said bowl is provided with two interior annular riiiles lil and lland a large annular concave rilile l5 designed to contain mercury inthis particular embodiment. There is also a discharge orifice 1Gprovided with a removable plug.

A central vertical feed pipe 1T is screwed into the bottom of' the bowll0 at a socket 1 8, and is provided with three openings near the saidsocket, one of which, lf), is shown. Said pipe 1T also serves as thedriving niemberrfor vthe bowl l0, and for this purpose' is provided witha driving pulley 2t). flhc upper end of the pipe 'l revolves in abearing 2l which is fitted into and held in place by a non-rotatingvertical pipe The latter fits into a center hole in the bracket 4.-, andis supported by a removable threaded collar Q3.

The lower end of the pipe is threaded into a socket in a stationarymassive ring' 24, which is maintained in concentric relationship withthe central revolving pipe 17 of the bowl 10 by means of a centerbushing 25 serving as an inner bearing. 0n the outside of theiixedpipeis located a simple clamp collar 26, held with set screws, and a flatdisc 27 is'locatedtlrereon and connected to the massive ring` 24 by ashort cylindrical section of pipe 28.Y The three n'iembers 24,-, 2T, and28 are joined to-y gether and supported by the pipe as will be evident,thus forming,` a single non-rotatiupmember, which may be termed an innerguide bowl. As will be seen, this is stationary in the embodiment nowbeing doscribed. i v

Above the disc n? is provided 'a ball bearing 29 on which runs an upperrotating hood bowlSO, which is suitably connected to and driven by ahorizontal pull-ey 3l providedwith abearing 32'. Saidhood bowl 30 has aninner annular"concavegroove that is provided with a number of disons`openings such as 34.

it 'will be seen that the space between the lower bowl 10 and the upperhood bowl 30 represented by .numeral 35 constitutes an annular dischargeorifice for the concentrates of higher density congegatingl againsttheiinside of the bowl 10, and this space 35 may be decreased orincreased by manipulation of the .screw 8 so that an opening as line as1/100 may bey obtained. A noteworthy feature of this structure is thatsuch a line adjustment may be made during the operation of theapparatus, therebyv making,` it possible to obtain a clean separationduring the running of the machine by observation of the nature andquality of the concentrate issuingthrough said opening- 35.

The dischar C'e of concentrates comin f j 7. s e t urough tne annularopenm 35 will fall into a suitably placed launder shown atr36. Theconcentrates lying,` inside of the outer ring of heavier concentratesmay be made to pass out through the openings 3d and will be dischargedinto an outer launder shown at 37.

A wooden plug 38 may be inserted in the bottom of the pipe 1T to closethe same below the orifices 19.

ln Fig. 2 a modification is illustrated, showing a construction in whichthe inner` bowl may be made rotatable. A cross member 2 carrying abracket 4, supports bearing 21 around a centrally fitted pipe 17. Acentral pipe 22 is mounted over the said bearing 21L and has screwed atthe upper end thereof a driving member 39 rotating` from ball bearing40. A bearing` l1 inserted in the bracket 4 serves to guide pipe 22. Thelatter is therefore made rotatable and consequently the correspondingmassive ring and inner bowl, described in detail in the aboveembodiment, will be made rotatable, all other parts of the structurebeing the same as in the above described preferred embodiment.

In the operation of the machine, a suitable rate of .rotation is `giventhereto and a charge of mercury is introduced into the feed pipe 17'andpasses into the bowl 10 through apertures y19. lThe centrifugal actioncauses .the mercury to ascend the sides of tl e bowl and fill the 13,1/1'-, and 15, any excess of mercury passing out through the opening',lhe machine is driven atits cfitical speed so that a vertical wallV ofmercury will be ietA -ned along the inside walls ol the bowl l()`without causing' any considerable quantity of this mercury to flow outthrough the opening' the purpose being to retain a watof menV in thebowl so that heavy metals .liie .Gold and platinum ill be re-v .edtherein :in their metallic staes,"and

:is over thev mercury and will rnalre their e'fit through the openingsand 3a respecl tively. r fter the wall of mereurj.'7 has been formed,water is turned in at 17 and subseeuentiy ore pulp or sands areintroduced and passed down the pipe 17 and into the bowl'lO. aqueousmixture to ascend the annular space between the bowl l@ and the innerbowl During this-time the materials are separated according' to theirspeciiic gravitiee. and are arranged in concentric annular layers orcolumns.` Consequently, by properly adjusting 'the width of the opening`35, the outer heavier layer of concentrate may be removed while theinner layer passes on up and may be removed through the openings 34. lnthe present machine only two such means ol removing concentrates areshown, but it will be understood that more than two openings may beprovided for line concentrates. y

ln the embodiment illustrated, tlir'ee separations are effected- (l)heavy metals such as g'olu and platinum in'ibed themselves in themercrry with` in the rililes, and they will bevrecover d when themachine is stopped and the mercury is withdrawn through the opening` 16.

(2l the nent heaviest remaining' mineral particles will be dischargedthrough the annularopening 35.

and the tailings or least heavy minerals will be obtained through theopening` 341-.

'ille adustability of the opening' 35 dpermits a very line cut-out to beobtained so that the outer layer of mineral concentratesl may be almostentirely taken oli' without iemoving the other materials positionsM iu.-teriorly thereof. U

iin especial feature of this invention consists in the inner bowl 28whichl may be 'lhe centrifugal actionv causes the till either fixed orrelatively rotatable as illustrated. It is not always possible duringthe centrifugal treatment of minerals and similar materials to get allof the heavier constituents on the outside ring of concentrates withouthaving imbedded therein some of the lighter materials. The tendency isfor the heavier particles to seek the outer circumference duringcentrifugal action and to pin downand hold lighter particles, so thatthe normal tendency of the latter to escape inwardly is prevented by thestrong pressure exerted by the heavier particles outwardly. rIheprovision of the inner bowl Q8, however, causes a differential rotationVof the particles lying between it and the inner wall of the bowl 10: inother words, the position of the particles is periodically changed bythe friction of the bowl 2S, thereby releasing the lighter particles andallowing them to escape inwardlyY to their proper positions asdetermined by their gravities. It will Vbe seen that for Vthus purposethe bowl 2S may be fixed or rotatable, the desideratum being to securethe relative movement between said bowl 28' and said bowl l0.

It will furthermore be seen that there is provided a vertical column ofmercury reif'olif'ing in the form of a true cylinder, and that thiscylinder of mercury is sufficiently long to provide a course of travelfor the mineral particles and water moving upwardly, thereby enablingthe minerals to position themselves according to their lgravi- 'ties inconcentric layers. Although the action of the centrifugal forces is veryrapid, the mineral particlesmust nevertheless be given sufficient timein which to find their proper positions. In the structuie shown herein asufficiently long course of travel provided to produce this result, andconsequently a very pure mineral concentrate maybe taken off through theopening 85, the purity of this concentrate beine' enhanced by thepresence of the inner bowl Q8.

The present form of machine is particularly advantageous in thetreatment of fine sands, clean-ups from dredging operations, andconcentrating sulphide minerals. For example, it will Succeed inseparating fine slime, galena, and sphalerite concentrates from eachother, an operation which is otherwise verydifiicult. The machine may beused profitably to separate fine gold and platinum in metallic form fromfine minerals or from otherwise worthless sands.

It will therefore be evident that an ap paratus has been devised in suchform and proportions that it will be capable of treating materialsotherwise difficult of treatment, so as to recover valuable mineralstherefrom in a very simple and effective manner. The presence of anupper bowl makes it possible to secure a very tine adjustment of thefirst discharge opening during running of the centrifuge; and thepresence of the inner bowl makes it possible 'to secure a differentialrotation of materials undergoing treatment so that each particle will,during' the course of the treatment, be given a free opportunity toescape into its proper zone according to its density.

As many apparently widely different embodiments of this invention may bemade without departing' from the spirit thereof, it is to be understoodthat I do not intend to limit myself to the specific embodiment thereofexcept as indicated in the appended claims.

I claim:

i. In a centrifugal machine, the combinationA of a bowl mounted forrapid rotation and having inner vertical sides provided with a concavityto hold a column of mercury, iffles in said sides below said concavityto also receive said nicrcury and heavy metal particles, said bowl beingmounted for rapid rotation; and stationary means contacting with theinner portion of the material undergoing treatment for effecting adiii'cren* tial movement within a mass subjected to centrifugal force insaid bowl.

2. In a centrifugal machine, the combination of a bowl mounted for rapidrotation and having vertical sides provided with a shallow concavity tohold a column of mercury and free from abrupt obstruction above saidmercury column, stationary means contacting with the inner portion ofthe material undergoing treatment to effect a differential movementtherein; an upper bowl mounted for rapid rotation and means for rotatingit independently of the lower bowl, said bowl being fixed againstvertical motion; and a vertical adjustable pivot point upon which thefirst named howl rotates whereby the space of the cutout between thebowls may be adjusted to any desired size.

3. In a centrifugal machine, the eomhina tion of a. bowl mounted forrapid rotation and having inner vertical sides io hold permanently avertical annular wall of mercury, ritlles in said sides below saidannular wall to receive mercury and heavy metal particles, said bowlbeing mounted for rapid rotation, and stationary means contacting withthe inner portion of the material undergoing treatment for effecting adifferential movement within the mass subjected to centrifugal force insaid bowl.

Il. In a centrifugal machine, the combination of a bowl having verticalinner sides and mounted for rapid rotation on a vertically adjustablepivot; an upper bowl mounted for rapid rotation but lined againstvertical movement, said upper bowl having an aperture for the dischargeof lighter concentrates.

In a centrifugal machine, the combination lof a bowl having Verticalinner sides and mounted for rapid rotation on at vertically adjustablepivot; an upper bowl mounted for rapid rotation but fixed againstAvertical movement, said upper bowl having with the inneil portion ofthe material miden going treatment to effect a differential movementtherein. 10 In testimony that I ciaini the foregoing,

I hve hereunto sei. my hand this 25th day of August, 1923.

JOHN M. NICOL.

